Pin grinding machine



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PIN GRINDING MACHINE Filed'Apr'il 17, 1947 9 Sheets-Shea?l 9 Patented July s, 194e UNITED STATES PATENT oFFicE PIN GRINDING MACHINE Basil H. Hackman, Waukegan, lll.

Application April 17, 1947, Serial No. 741,976

16 Claims.

This invention relates to a pin grinding machine and more particularly to such a machine for grinding tapered points on the steel pins which are used in lapping operations in making tungsten carbide wire drawing dies. Heretofore. grinding machines of this nature had to be hand operated and each pin was inserted and removed from the grinding machine by hand. thus resulting in excessive labor costs and slow operation. It was also diiiicult to change the angle of the taper on the pin.

It is an object of this invention to provide a pin grinding machine which is fully automatic and only requires an operator to place the pins in a feeding hopper and to remove the finished pins from a receiving hopper.

Another object is to provide such a device in which the taper ground on the pin may be readily varied.

These and other objects will be more apparent after referring to the following specification and attached drawings, in which:

Figure 1 is a plan view of the entire machine. with dot-and-dash lines to indicate certain movements; g l

Figure 2 is a side elevation, partly in section, showing all three spindle positions and operations;

Figure' 3 is a view taken on the line III-III of Figure 2 and showing the indexing gears and collet-opening mechanism;

Figure 3A is a view of a part broken out, of Figure 3 and showing the bottom of the hopper:

Figure 4 is a plan view, partly in section, of the spindle construction,- collet mechanism, and a typical grinding position of the grinder;

Figure 5 is a view of a pin in a pin holder;

Figure 6 is a fragmentary view along line VI-VI of Figure l;

Figure 7 is a plan view, partly in section, of the fixed collet-opening cam taken on the line VII-VII of Figure 2;

Figure 8 is a view taken on the line VIII-VIII of Figure 2 and sho1 ing the face of the indexing pin plate or disk;

Figure 9 is a sectional view taken on the line IX-IX of Figure 10 and showing the turret plates assembled with spacers:

Figure 10 is a view taken on the line X-X of Figure 2;

Figure 11 is a sectional view of the spindle drive taken on the line XI-XI of Figure 12;

Figure 12 is a sectional view taken on the line XII-'XII of Figure 11;

Figure 13 is a sectional view taken on the line XIII-XIII ot Figure 12:

Figure 14 is a diagrammatic view of the air system in relation to the cam position .when the plungers are retracted;

Figure 15 is a view similar to Figure 14, but showing the cam position when the plungers are loading and ejecting;

Figure 16 is a view taken on line XVI-XVI of Figure 2 and showing the air system cam and valve when the plungers are in the position shown in Figure 15;

Figure 17 is a view taken on the line XVII-XVII of Figure 2 and showing the grinder cam position at the start of grinding;

Figure 18 is a fragmentary view similar to Figure 17, but showing the grinder cam position when the grinder is retracted from the pin being ground:

Figure 19 is a side elevation, partly in section, of the grinder base;

Figure 20 is a transverse section taken on the line XX-XX of Figure 19.

The following ngures are all of the "collet clod" position, with the index pin in the index pla l l Figure 21 is a view taken on the line XXV- XXV of Figure 2 and showing the collet opening cam when the collet closed position and the index pin in the index plate;

Figure 22 is a side elevation of Figure 21;

Figure 23 is a view taken on the line XXV- XXV of Figure 2 and showing the index pin operating cam when in the collet closed position' A;

Figure 24 is a side elevation of Figure 23;

Figure 25 is a view taken on the line XXV-XXV of Figure 2 and showing the collet opening cam with the index pin cam 'set within it when in the colletclosed position A;

Figure 26 is a side elevation of Figure 25.

The following iigure is in the collet open" position, and when the index pin is moved outwardly from the index plate:

Figure 27 is a view similar to Figure 25, but showing the position of the cams in the collet open position and the index .pin out of the index pla e.

rReferring more particularly to Figure 1 of the l drawings, reference numeral 2 indicates a' base on which a grinder l and a plate B are mounted.

extending upwardly from the plate 2 through a slot i2 in the plate 6. The entire mechanism with the exception of grinder 4 is mounted on the plate 6. The pins P to be ground are placed in a hopper I4 with their pointed ends directed toward the main portion of the machine. Preferably the pins P are gripped in a holder or chuck |6 as shown in Figure 5. As shown in Figures 3 and 3A, the hopper I4 is made of sheet metal and is provided with a diagonal plate |6 which separates the hopper into top and bottom sections. Adjacent the left hand end of the hopper, as seen in Figure 3, is a baille plate I6 which assists in directing the pins P into an inclined runway extending along the bottom of the hopper. The lowestl point in the hopper is provided with openings 22 at each end thereof which permits the lowest pin in the runway 20 to be discharged from the hopper by means of an air actuated plunger 24 mounted in a cylinder 26. As shown in Figure 1, the cylinder 26 is mounted on a frame 28 bolted or otherwise fastened to the plate 6 and is provided with air conduits 30 and 32, one at each end thereof. An indexing head assembly, carried in a frame 34, is located adjacent the discharge end of hopper I4. 'I'he indexing head shaft 36 is mounted in bearings 38 which are supported in the frame 34. As best shown in Figures 2, 9 and 10, two

plates 40 are xed upon shaft 36 in spaced apart relationship and support three collet carrying spindles 42 therebetween. These spindles are positioned 120 apart and are rotatablysupported in bearings 44, which in turn are supported by the plates 40. Each of the spindles 42 supports a V-pulley 46 for receiving a friction drive which will be referred to later. As shown, the pulley 46 is integral with the spindles 42, but it will be understood that it may be a. separate part secured to the spindles. Plates 40 are held in spaced apart relationship by means of spacers 46. As best shown in Figure 4, each of the spindles I42 is hollow and carries therein a spring loaded collet assembly which includes a tubular collet actuator portion 50 having a threaded end portion which carries a collet actuator nut 52. The outside diameter of the actuator portion 50 is reduced at its left hand end as shown in Figure 4 to enable a collet actuator spring 54 to fit thereover. tained under compression at all times by a spring retainer nut 56 which is threaded into the left hand end of the hollow spindle 42. The right hand end of tubular member 5|) has an enlarged recessed portion 58 in which is slidably mounted a coil actuator insert 60 which, in turn, receives a standard Ericson collet 62. A collet nut 64 threaded onto the spindle 42 retains the collet 62 in position. In order to open the collet assembly it is necessary to move the tubular member 56 to the left as shown in Figure 4 and thus allow the insert 60 to be forced to the left by the expanding force of the slotted Ericson collet 62. The member 50 is moved by a collet opening slide 66 (Figure 2), slidingly supported in the frame 34 by a bushing 66. The slide 66 is provided with an axial opening 10 which is aligned with the openings 22 in the hopper .|4 through which the pins P are fed into the collet assembly. A nut 12 is threaded onto the left hand end of slide 66 and is provided with lugs 14 which llt within openings 16 in a lever arm 16. As shown in Figure 3, the lever arm 'I6 is pivotally supported on a pin 60 with its free end extending downwardly and supporting a cam follower 62 which follows the cam track 64 of a cam 66 Spring 54 is main' mounted on the cam shaft 66.. As shown in FiguresA 21 and 22, the cam track 64 has a 120 high portion A, a 220 low portion B and 20 ramp portions D and C between portions A and B Mounted on the shaft 36 adjacent the right hand end thereof (as seen in Figure 2) is an indexing plate 60 which is provided with three equally spaced openings 62 therethrough as shown in Figure 8. The indexing head has three positions. position #1 being the loading position, position #2 being the grinding position, and position #3 being the discharging position. Adjacent position #l the frame 34 is provided with openings 64 and 96, opening 94 slidably receiving a pin stop 66 and opening 60 slidably receiving a positioning pin |60. As shown in Figure 2, pin stop 66 and positioning pin |00 are threaded over one-half of their lengths and are adjustably secured in a member |02, which in turn is pivotally secured to the upper extremity of a lever arm |04. The lever arm |04 is pivotally supported on a pin |66 mounted on the frame 34 and its lower extremity is flexibly secured to one end of a tie rod |06 which passes through the frame 34 and has its opposite end flexibly connected to a lever ||0 located outside of frame 34. A spring ||2 surrounds the rod |08 between the lever |64 and the frame 34, thus urging the pin stop 66 and positioning pin |00 to the left. The lever ||0 is pivotally mounted on a pin ||4 with the free end of the lever extending upwardly and suporting a cam roller ||6 which follows the face of a cam H6. The cam ||6 is mounted on cam shaft 66 and is held in place thereon by means of a tapered pin |20. As shown in Figures 23 and 24, the cam H6, has a 240 low portion E, an high portion F and 20 ramp portions G and H betweenportions E and F. As shown in Figures 24, 26 and 27, a hub |22 extends outwardly from the cam 8 and supports the cam 66. Threaded openings |24 are provided in the cam 66 for receiving countersunk screws which pass through openings |26 in the cam H6.

As shown in Figure 1, the cam shaft 66 is driven from a ratio motor |26 through a drive shaft |30 and coupling |32. An indexing gear |34 provided with five teeth is mounted on cam shaft 66 adjacent the earn H6 and a plate |36 is secured thereto by cap screws |38. The plate |36 is circular, but has a reduced diameter through 74, as shown in Figure 3.

The shaft 36 extends through the frame 34 and has an indexing pinion |40 secured to its left hand end which meshes with gear |34. An indexing plate |42 is secured to the pinion |40 by cap screws |44. In practice, the speed of the motor |26 and the relationship between indexing gear |34 and indexing pinion 40 is such that the indexing gear |34 will mesh with the pinion |40 every thirty seconds to advance the entire indexing assembly to its next position. Cams 66 and ||6 are so positioned on shaft 88 with respect to the indexing gear |34 that the pin stop 66 and positioning pin |004 will be withdrawn just prior to the meshing of the teeth on gear |34 with the teeth on pinion |40' and the collet opening slide 66 will be held in position to prevent the opening of the collet until an empty collet has been presented thereto at the end of 120 of travel from the electing position. The plate |42 has three concave portions |46 on its outer periphery, the radius of each portion being equal to the radius of the outer periphery of plate |36 so that plates |36 and |42 will mesh with respect to each other and aiford a secondary means for maintaining the indexing head assembly in any one of its three positions.

When the indexing head with the pin P therein is. advanced to position #2, its V-pulley 48 contacts a driven Bakelite friction wheel |48, which is keyed or pinned to a gear |80 as shown in Figure 12. 'I'hewheel |48 and gear |80 are fastened to a shaft |82 supported in bearings |84 which are mounted in rocker plates |88. The gear |80 meshes with a gear |88 which is rotatably mounted on a shaft I 80 and is held in its desired position thereon by means of hollow shafts |82 and |84. The hollow shafts are fixed to the shaft |80 by means of screws |88 passing through the outer ends thereof. The hollow shafts |82 and |84 are mounted in a spindle stand |88 and are held from rotation thereon by means of set screws |10. The spindle stand |88 is fastened tothe plate 8 by means of cap screws |12. 'I'he rocker plates |88 are pivotally supported on bushings |14 mounted on the hollow shafts |82 and |84. Brackets |18 are fastened to the bottom of the friction wheel assembly and a boit |18 extends outwardly therefrom and supports a 'plate |80. Screws |82 pass through the plate |80 and are screwed into the spindle stand |88. A spring |84 surrounds each of the bolts with one end bearing against a nut |88 and the other end against the plate |80, thus providing for a yielding contact of the wheel |48 and the pulley 48. 'I'he gear |88 meshes with a gear |88 fixed to the shaft of motor |80.

After the pin to be ground is advancedl to position #2 of the indexing head and the spindle 42 is rotating, the grinding operation is started. As shown in Figures 1 and 4, the grinder motor |82 carries a grinding wheel |84 at the end of its shaft |88. As shown in Figures 19 and 20, the motor |82 is mounted on a plate |88 which in turn is slidably supported by a saddle 200 by means of four ball bearings 202 which are confined in a pair of trackways 204. 200 is slidably gibbed to the grinder slide base 208 which is iixedly secured to the base plate 2 by means of bolts 208. A bolt 2i0 passes through slots 2|2 in the saddle 200 and is provided with nuts 2|4 bearing against the sides of the saddle to hold it in position. As shown in Figure 1, the bolt 2|0 is threaded into a member 2 |8 which is pivotally connected to a lever 2|8 mounted on a bolt 220 fastened to plate 8. The other end of lever 2| 8 is pivot'ally connected to one end of an arm 222, the other end of the arm 222 being bifurcated to receive the central portion of a link 224 which is fastened thereto by means of a pin 228. One end of the link 224 is pivotally secured to the frame 34 by means of a bolt 228 and the other end carries a cam follower 288 which follows the track of a cam 232 which is fastened to shaft 88. Movement of the grinder in a direction parallel to the point of a pin is accomplished through a ratio motor 234, shaft.

238, eccentric disk 238 and link 240 which is connected to the motor |82 by means of a bolt 242. The ratio motor 234 is an electric motor Iused in connection with a gear reducer with its shaft 288 extending upwardly. The upper end of the shaft 238 has the eccentric disk 288 connected thereto with the connecting bar 248 being pivotally connected to one of two holes 244 in the eccentric disk 238,'the holes Ibeing at different distances from the center of the disk 238 to provide for adjustment of the length of the The saddle stroke of the grinder. The cam 282 brings the grinder into contact with the Din' P on its 240. dwell portion and out of contact on the i:- maining 120. The movement of the cam 282 is timed with the movement of the pin positioning the pin stop cam' ||8 whose 240 dwell portion holds the pin positioning p in |88 and the stop pin 88 in the position shown in Figure 2, thereby holding the indexing head in position while the grinding of the pin is taking place during the 240 dwell of theggrinder cam 282. The grinder moves away from the pin during the 40 fall of cam 282 and toward the pin during the rise. While the grinder is moving away, cam ||8 causes the positioning pin and pin stop to move outwardly and allow the indexing head to be advanced by the partial gear |84. As the indexing head moves through 120 the spindle which was previously in position #2 advances to position #3 and as it comes into this position the collet actuator nut 82 contacts a fixed cam 248 (Figure 2) which urges it outwardly, thus removing the compressive force of spring 84 against the tubular section' 88 which retains the Ericson collet 82 in a closed position. Therefore, when spring 84 is compressed, collet 82 is allowed to expand and free the pin P.

As shown in Figures 14 to 16, a four-way air valve 248 is mounted adjacent the cam shaft 88 with its valve stem 288 extending toward a cam 282 fastened to the cam shaft 88. A cam roller 284 is carried by a yoke 288 secured to the end of a yoke stud 288 which in turn is slidahly supported in a bearing 288. The valve 248 and bearing 280 are mounted on top of a bracket 282. An.

air cylinder 284 (Figure 2) is mounted adjacent the frame 84 which is provided with an opening 288 in line with the collet'in position #3. A plunger 288 is actuated by, cylinder 284 and moves forward into the spindle opening 10 to eject the pin contained therein as soon as the collet 82 releases the pin which falls into a receiving pan 210. The air cylinder 284 is provided with con-- duits 212 and 214 at opposite ends thereof.

The operation of the device is as follows:

Pins P are placed in the hopper I4 as shown in Figures 1 and 3. The plate 8 is turned on its pivot 8 to provide the right taper for the pin being ground and is then locked in place by means of the bolt and nut I0. The motors |28, |80, |82 and 234 are started in operation. This starts the cam shaft .88 rotating and with it the cams mounted thereon. Cam 282 is so arranged that when an empty collet reaches position #l the four-way valve 248 is moved to admit air into the left hand end of cylinder 28, thus enabling the plunger 24 to shove the bottom pin P out of the hopper |4 through the opening 10 into the collet 82 which grips the pin. At the same time, cam ||8 will move the pin stop 98 and positioning pin |00 into the position shown in Figure 2, thus locking the indexing head in position and positioning the pin P in the correct axial position. Also, at

the same time, the cam 282 causes the lever 2|8 to rotate about its pivot 220 and move the grinder against the pin P in position #2, this motion t. being at right angles to the surfaceto be ground.

As described hereinbefore, the grinding wheel |84 will be in contact with the pin on the 240 dwell portion of the cam 232. Motor 234 through its associated mechanism' will reciprocate the grinding wheel |94 to grind the surface of the pin P. Meanwhile the collet in position #3 will have been opened by contact of the nut 82 on the cam 248. -Also at the same time air will be admitted.

through conduit 212 to force the machined pin P in position #3 out of the collet and into the pan 210. Continued movement of the cam 252 changes the position oi' the four-way valve 24| to introduce air into the right hand end of cylinders 26 and 264 to retract their respective plungers. It will be understood that during the grinding operation the collet in position #2 will be rotated by means of the pulley 48 contacting the wheel |48. After the grinding operation has been completed, continued movement of the cam ill retracts the pin stop 9B and positioning pin |00. Meanwhile the indexing gear i3! has rotated until the teeth thereon meshes with the teeth of pinion Idil, thus rotating the indexing head through 120. The indexing head is then in position to receive another pin P from the hopper it and the operation is repeated.

While one embodiment of my invention has been shown and described it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claims.

I claim 1. A grinding machine for grinding a taper on pins comprising a base, a grinder mounted on said base, a plate adjacent said grinder pivotally mounted on said base adjacent said grinder, a frame mounted on said plate, a shaft rotatably mounted in said frame with one end extending therefrom, an indexing head mounted on said shaft for movement therewith to three diderent positions, said positions being the loading, grinding and discharge positions, three collets arranged on said indexing head in spaced apart relationship with their axes parallel to the axis of said shaft. jaws associated with each collet for gripping one of said pins, a rotatable cam shaft, a cam mounted on said cam shaft for opening said Jaws at the loading position, means for feeding a .pin axially into said collect at the loading position, a second cam mounted on said cam shaft for actuating said feeding means after the jaws of the collet at the feeding position are open, said first named cam causing said last named jaws to close after the pin is fed therein, a pinion mounted on the extended end of the indexing head shaft, a partial gear mounted on said cam shaft and adapted to mesh with said pinion to rotate the indexing head at intervals from position to position, means for rotating the collet in the grinding position, means foi` opening the jaws of the collet at the discharge position, and means for discharging the pin from the collet at the discharge position.

2. A grinding machine for grinding a taper on pins according to claim 1 in which a hopper is provided adjacent the feeding means for receiving said pins, said hopper having an axial opening through the bottom' thereof in line with the axis of said collet, said feeding means including a rod adapted to reciprocate in said axial opening.

3. A grinding machine for grinding a taper on pins according to claim 2 in which a stationary cam is mounted on said frame to actuate the jaw opening means at the discharge position.

4. A grinding machine for grinding a taper on pins according to claim 3 in which the second cam on said cam shaft actuates the discharge mea-ns after the Jaws ofthe collet at the discharge position are opened.

5. A grinding machine for grinding a taper on pins according to claim 4 having means for moving the grinder against the pin, a third cam mounted on said cam shaft for actuating the grinder moving means when a collet reaches the grinding position.

6. A grinding machine for grinding a taper on pins according to claim 5 having movable means limiting the axial movement of the pin at the loading position and a fourth cam mounted on said cam shaft for actuating the said limiting means when a collet reaches the loading position.

7. A grinding machine for grinding a taper on pins according to claim 6 having an indexing plate mounted on the indexing head shaft, said indexing plate having three spaced apart openings therein with their axes parallel to the axis of the indexing head shaft, said frame having an opening in said frame adjacent the loading position, a pin, means for moving said pin through said last named opening into one of the'openings in the indexing plate, said fourth cam actuating said pin moving means at the same time as it actuates the said limiting means to loci: the indexing head in position.

8. A grinding machine for grinding a taper on pins according to claim 1 in which a stationary cam is mounted on said frame to actuate the Jaw opening means at the discharge position.

9. A grinding machine for grinding a taper on pins according to claim 8 in which the second cam on said cam shaft actuates the discharge means after the Jaws of the collet at the discharge position are opened.

10. A grinding machine for grinding a. taper on pins according to claim 9 having means for moving the grinder against the pin, a third cam mounted on said cam shaft for actuating the grinder moving means when a collet reaches t 40 loading position and a fourth cam mountedion said cam shaft for actuating the said limiting means when a collet reaches the loading position.

12. A grinding machine for grinding a taper on pins according to claim 11 having an indexing plate mounted on the indexing head shaft, said indexing plate having three'spaced apart openings therein with their axes parallel to the axis of the indexing head shaft, said frame having an opening in said frame adiacent the loading position, a pin, means for moving said pin through said last named opening into one of the openings in the indexing plate, said fourth cam actuating said pin moving means at the same time as it actuates the said limiting means to lock the indexing head in position.

13. Indexing mechanism for positioning pins for machining which comprises a frame, a shaft rotatably mounted in said frame with one end extending therefrom, an indexing head mounted on said shaft for movement therewith to at least three different positions, said positions being the loading, machining and discharge positions, at least three collets arranged on said indexing head in spaced apart relationship with their axes parallel to the axis of said shaft, each of said collets having an axial opening therethrough, Jaws* associated with each collet for gripping one of said pins, a rotatable cam shaft, a cam mounted on said cam shaft for opening said jawsy at the loading position, means for feeding a pin axially into said collet at the loading position from the rear end thereof with the pin being moved to the correct axial position, a second cam mounted on said cam shaft for actuating said 9 feeding means after the laws of the collet at the feeding position are open, said first named cam causing said last named jaws to close after the pin is fed therein, a pinion mounted on the extended end of the indexing head shaft, a partial gear mounted on said cam shaft and adapted to mesh with said pinion to rotate the indexing head at intervals from position to position, means for rotating the collet in the machining position, means for opening the jaws of the collet at the discharge position, and means for discharging the pin from the collet at the discharge position.

14. Indexing mechanism according to claim 13 in which a stationary cam is mounted on said frame to actuate the jaw opening means at the discharge position.

15. Indexing mechanism according to claim 14 in which the second cam on said cam shaft actuates the discharge means after the jaws of the collet at the discharge position are opened.

16. A grinding machine for grinding a taper on pins comprising a grinder, a frame adjacent said grinder, a shaft rotatably mounted in said frame with one end extending therefrom, an indexing head mounted on said shaft for movement therewith to a plurality of positions, said positions including the loading, grinding and discharge positions, at least three collets arranged on said indexing head in spaced apart relationship with their axes parallel to the axis of said shaft, each of said collets having an axial opening therethrough, jaws associated with each collet for gripping one of said pins, a rotatable cam shaft, a cam mounted on said cam shaft for opening said jaws at the loading position, means for feeding a pin axially into said collet at the loading position from the rear end thereof with the pin being moved tothe .correct axial position, a second cam mounted on said cam shaft for actuating said feeding means after the jaws of the collet at the feeding position are open, said first named cam causing said last named jaws to close after the pin is fed therein, a pinion mounted on the extended end of the indexing head shaft, a partial gear mounted on said cam shaft and adapted to mesh with said pinion to rotate the indexing head at intervals from position to position, means for rotating the collet in the grinding position, means for opening the jaws of the collet at the discharge position, and means for discharging the pin from the collet at the discharge position.

BAZIL H. HACKMZAN.

REFERENCES CITED The following referenices are of record in the nie of this patent:

UNITED STATES PATENTS Number Name Date 1,516,103 Keller Nov. 18, 1924 1,888,710 Arter et al Nov. 22, 1932 1,898,648 Thorsen et al. Feb. 21, 1933 1,999,321 Dunham Apr. 30, 1935 2,003,269 Arter et al May 28, 1935 2,109,600 Vanderbeek Mar. 1, 1938 FOREIGN PATENTS Number Country Date 573,117 Mar. 28, 1933 

